The pump of this invention is in the same field as the pumps shown in the following U.S. Pat. Nos. 2,187,684, 2,636,441, 2,787,225, 3,469,532, 3,502,029, 3,945,772, 4,487,340, 4,762,474, and 6,102,676, the latter of which is directed to a lance pump sold by Lincoln Industrial Corporation of St. Louis, Mo. under the trademark Flow Master®. While the Flow Master® pump has proven to be commercially successful, there is a need for increasing the output of the pump when the pump is used to pump stiff greases.